Analysis of the Relationship Between Prism, Diastolic Dysfunction, and Obesity

Abstract Rationale: Preserved ratio impaired spirometry (PRISm), defined by a ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) greater than the lower limit of normal (LLN) with FEV1 and/or FVC less than the LLN, is linked to increased respiratory symptoms and cardiovascular mortality. This pathology remains poorly understood partly due to heterogeneity. Studies suggest a metabolic subtype of PRISm in individuals with high body mass index (BMI) and cardiovascular comorbidities. This may overlap with an obese phenotype of heart failure with preserved ejection fraction (HFpEF). This study aims to assess the relationship between PRISm and diastolic dysfunction in obese patients. Methods: This retrospective cohort study compared subjects with PRISm to those with normal spirometry, all with a BMI ≥ 35. Those with interstitial lung disease and systolic heart failure were excluded. Data reviewed from electronic health records included demographic information, comorbidities, pulmonary function tests, echocardiograms, chest computed tomography (CT), and healthcare utilization. Diastolic function was assessed with echocardiographic measurements, including the ratio of early mitral inflow velocity to early diastolic mitral annular velocity (average E/e’) and estimated pulmonary artery systolic pressure (PASP). We then calculated H2FPEF scores, a validated tool for estimating the likelihood of HFpEF. The association of PRISm with diastolic dysfunction was tested with multivariable linear regression. Results: Individuals with PRISm (n = 97; 52%) were similar to those with normal spirometry (n = 91; 48%) regarding age, gender, and smoking history. The PRISm group had a significantly greater BMI and higher incidence of coronary artery disease and diabetes mellitus. PRISm status was significantly associated with higher average E/e’ and estimated PASP (Figure 1). After adjusting for age, gender, BMI, smoking history, and comorbidities, both average E/e’ (β = 1.95, p = 0.003) and estimated PASP (β = 7.58, p = 0.004) remained significantly associated. H2FPEF scores were significantly higher in the PRISm group (p = 0.008). The two groups had similar numbers of urgent care visits, emergency room visits, and hospitalizations over a three-year period. Conclusion: In obese individuals, PRISm status is independently associated with diastolic dysfunction and higher clinical scores for HFpEF. This often overlooked spirometric pattern may contribute to a distinct cardiac risk profile. The mechanism underlying this relationship deserves further research.